Cutting head for electric shavers having a helical shaped movable cutter



April 14, 1964 A. MlsELLl 3,128,550

CUTTING HEAD FOR ELECTRIC sHAvERs HAVING A HELICAL SHAPED MOVABLE CUTTER Filed Aug. 29, 1962 .22j Q E 7. INVENTOR Afro Mzls'ellz' #Y E@ MM- ATTORNEYS United States Patent O Filed Aug. 29, 1962 ser. No. 220,306 s Claims. (ci. alo- 43) This invention relates to a cutting head for an electric razor.

Electric razors by virtue of their practical and convenient nature have now become acceptable throughout the world and are based on the principle of passing over the skin the outer surface of a very thin grid plate having small perforations through which the separate bristles project, there being in contact with the inner surface of said plate cutting blades which, by unidirectional or alternating rotation or by vibration, remove the parts of the bristles which project through the plate. Although apparently simple, this method of operation of conventional electric razors is not in practice free from serious dirsadvantages. One of these resides in the fact that the known razors do not as a rule cut the bristles but crumble and pulverize them, necessitating passing the razors several times over the skin. This occurs because the separate bristles, when coming into contact with the cutting blades, tend to evade the action of the latter and at least in part escape it, so that it will always be necessary to pass over the same area of skin several times. This is the reason moreover why the bristles are crumbled and reduced to powder when using conventional electric razors.

Also, razors at present available are very noisy and, owing to pulverization of the bristles, their cleaning and maintenance require special care.

A cutting head, according to the invention, includes a rotor including a plurality of co-axial cutting discs one segment of each of Which presents a helical pitch opposed to that of the succeeding segment and a spindle on which the discs are mounted at such inclination to the axis of the spindle as to produce a helix which, during its rotary motion, permits a crossing spiral cut to be performed to shave ol substantially all hairs projecting through perforations in a grid plate covering the rotor.

One embodiment of the invention is illustrated by way of example only in the accompanying drawings in which:

FIG. l is a cross sectional view of the cutting head taken on the axis of the cutter spindle, showing the external view of the discs;

FIG. 2 is a cross sectional view taken at right angles to the axis of the cutter spindle along the line II-II of FIG. l;

FIGS. 3 and 4 illustrate, respectively, a side elevation and a front elevation of a disc;

FIG. 5 is a cross sectional view taken on the line V-V of FIG. 4;

FIG. 6 is a cross sectional view on a reduced scale taken on the axis of the spindle and through the discs of FIG. l;

FIG. 7 is a plan View of the covering sheath or case of FIGS. l and 2 for the working head incorporating a grid plate;

FIG. 8 is a cross sectional View of the sheath or case of FIG. 7 showing the grid plate configuration in the secured position as well as when in the released position;

FIG. 9 is a perspective view on a reduced scale of the grid plate of FIGS. 7 and 8 to which is applied a spring according to the invention, and

FIGS. 10 and 1l illustrate respectively, a side view and and end view of one fixed end wall of the cutting head.

Referring to the drawings, the cutting head forming the subject of the invention comprises a sheath or case 12 which is itted to the base 13 of the head and is secured thereto at one end bymeans of screws (not shown) passing freely through the openings 14 and into the threaded openings 14 provided in opposite sides of the fixed upright wall 18, said screws serving as a hinge pivot to provide for cleaning of the appliance after use. At the other end, the sheath 12 is secured to the base 13 by means of a spring catch 16 engaging in a recess formed in the side of the sheath or case 12 and operated by means of a plunger 17 which slightly projects out of the sheath or case.

Two spaced apart, upright brackets 19 and 21, unitary with the base 13, carry respectively the posts 22 and 23 supporting therebetween a spindle 20 on which are mounted a series of helical cutter discs 27. The bracket 19 rotatably supports a horizontal shaft4 or pin 24 on which is keyed a pinion 25. The pinion 25 which is driven by a small motor (not shown) meshes with a pinion 26 on Athe spindle 20 to rotate the spindle and the discs 27 in the desired direction. The wall 18 is attached tothe bracket 19 by screws (not shown) passing through openings 38 formed therein and into the threaded openings 40 formed in the wall 18. The discs are shown in more detail in FIGURES 3, 4 and 5 which illustrate the cutting edges, a front view and a section, respectively.

Referring to FIG. 6 in particular, there are clearly shownv the spindle 20, the discs 27 and spacing washers 20 located between the discs.

Each of the discs include two segments which are stamped out in such manner as present two aligned, radial cutouts 28, 29 producing points A, B, C, D at the periphery of the disc and delineating the inversion of the helical pitch and with the two segments together forming a spurious helix of which one half, as seen in FIG. 1, follows a pitch in one direction, while the other half (not visible FIG. l) follows a pitch in the opposite direction despite the single direction of rotation of the spindle. The inversion of said helical pitch of each disc 27 occurs in correspondence with the cutouts 28, 29 and more precisely with the points A, B, C, D where the inclination of the disc vanes is equal to zero. As shown in the drawings, the segment terminating at points A, C, may be considered to be a righthand helix and the segment terminating at points B, D a left-hand helix.

Particular reference is made to the cutting edge 27 of the discs 27. As shown in FIG. l, the cutting edge 27' runs parallel to the grid plate 31 and is thus self-sharpening, during rotation of the discs, to a degree depending on the thickness of the material of the disc and on the inclination of the same relative to the horizontal. On the other hand, the fact that the cutting edge 27' bears lightly against the grid plate 31 also contributes to the sharpening and freedom from foreign bodies of the cutting edge.

The grid plate 31, which is of known type is provided on one side with openings 32 and is secured at said one side thereof to the sheath or case 12 by means of screws 32, the other side being formed with two holes 33 into which is inserted a small spring 34 carrying a catch 34' by means of which the grid plate is anchored through a hole 36 drilled opposite side from the screws 32. The purpose of the small spring 34 is to hold the grid plate 31 in contact with the disc rotor.

While one embodiment of the head has been given by way of example, the discs 27 may, for example, be mounted on two parallel spindles and present two shearing generatrices instead of a single one, and the grid plate may bear on the upper portion of the cylindrical curvature of the discs in partial match to their outline in such manner as to exhibit a reentrant portion corresponding to the space flanked by these two rotors.

The rotary cutter referred to may moreover be given a pitch or cutting line dilering from that referred to and may be rotarily driven by means of gears, a belt or a analogous means, and the discs mounted on the rotary spindle may moreover be fitted in various ways so that the spacing of said discs may vary between 2 and 7 mms. as the cutting action of one disc, is taken over before its cessation by that of the immediately adjacent disc, without any break in continuity.

A special advantage of the head according to the invention is that it does not cut a bristle in a shearing action at right angles to the axis of the bristle, but by the progressive advance of the helical cutter discs which tend to draw the bristle towards the interior of the head,

I thus largely making up for the thickness of the grid plate.

Another advantage resides in the fact that the grid plate always bears lightly against the cutting face of the discs, thus keeping them sharp and free of any foreign bodies. A further advantage is that the bristles are cut gradually, irrespective of whether they are stiff or pliable, and are thus severed smoothly ush with the skin.

What I claim is:

1. In a rotating cutter for a power driven razor having a perforated grid plate in contact with a plurality of nested cutting discs mounted on a spindle for rotation therewith, each of said cutting discs comprising: a body portion provided with a centrally disposed opening; said body portion having a segment thereof disposed on each of the opposite sides of a plane passing diametrically through said disc, the periphery of said segments providing cutting edges, one of said segments being formed with a right-hand helical pitch and the other of said segments being formed with a left-hand helical pitch, the periphery of said segments of said discs being cylindrical and coaxial with said opening for cutting in cooperating with said grid plate upon rotation of said spindle.

2. In a rotating cutter for a power driven razor having a perforated grid plate in contact with a plurality of cutting discs of equal diameter mounted on a spindle for rotation therewith, each of said cutting discs comprising: a body portion provided with a centrally disposed opening, said body portion having a segment thereof disposed on each side of a diametrical plane passing through said body portion, the periphery of said segments providing cutting edges, one of said segments being formed with a righthand helical pitch and disposed on one side of a plane passing through said body portion and normal to the axis of said opening, the other of said segments being formed with a left-hand helical pitch and disposed on the other side of said plane passing through said body portion and normal to the axis of said opening, the periphery of said segments of said discs being cylindrical and coaxial with said opening for cutting in cooperation with said grid plate upon rotation of said spindle.

3. In a rotating cutter for a power driven razor having a perforated grid plate in contact with a plurality of cutting discs of equal diameter mounted on a spindle for rotation therewith, each of said cutting discs comprising: a body portion provided with a centrally disposed opening and a pair of aligned, radial slits extending from the periphery of said disc inwardly toward the axis of said opening, dividing said disc into two segments, the periphery of said segments providing `cutting edges, one of said segments being formed with a right-hand helical pitch and disposed on one side of a plane passing through said body portion and normal to the axis of said opening, the other of said segments being formed with a left-hand helical pitch and disposed on the other side of said plane passing through said body portion and normal to the axis of said opening, the periphery of said segments of said discs being cylindrical and coaxial with said opening for cutting in cooperation with said grid plate upon rotation of said discs.

References Cited in the file of this patent UNITED STATES PATENTS 2,264,113 Ericson Nov. 25, 1941 FOREIGN PATENTS 219,671 Great Britain Nov. 20, 1924 

1. IN A ROTATING CUTTER FOR A POWER DRIVEN RAZOR HAVING A PERFORATED GRID PLATE IN CONTACT WITH A PLURALITY OF NESTED CUTTING DISCS MOUNTED ON A SPINDLE FOR ROTATION THEREWITH, EACH OF SAID CUTTING DISCS COMPRISING: A BODY PORTION PROVIDED WITH A CENTRALLY DISPOSED OPENING; SAID BODY PORTION HAVING A SEGMENT THEREOF DISPOSED ON EACH OF THE OPPOSITE SIDES OF A PLANE PASSING DIAMETRICALLY THROUGH SAID DISC, THE PERIPHERY OF SAID SEGMENTS PROVIDING CUTTING EDGES, ONE OF SAID SEGMENTS BEING FORMED WITH A RIGHT-HAND HELICAL PITCH AND THE OTHER OF SAID SEGMENTS BEING FORMED WITH A LEFT-HAND HELICAL PITCH, THE PERIPHERY OF SAID SEGMENTS OF SAID DISCS BEING CYLINDRICAL AND COAXIAL WITH SAID OPENING FOR CUTTING IN COOPERATING WITH SAID GRID PLATE UPON ROTATION OF SAID SPINDLE. 